If you downloaded via direct download - you might have gotten a corrupted file. There is little you can do about that... You must re-download it...

If you downloaded via torrent, you might have not finished the torrent completely. Or you might want to stop the torrent program before unzip... I don't remember putting anything in a zip file in the torrent actually...

Hmmm still not working... I've already tried downloading another file off the site, is it possible that the download link itself is corrupted? The only thing i haven't tried is using the torrent file but thats taking way to long but ill try and tough it out.